Codeforces Round 782 (Div. 2)

Solutions for Codeforces Round 782 (Div. 2) (contest 1659). 2/6 problems verified against sample I/O. Difficulty range: 1000-3000.

6 items

Codeforces Round 782 (Div. 2)

Type: Div. 2 | Problems: 6 | Verified: 2/6 | Rating range: 1000-3000 | Time: 23m 58s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Red Versus Blue	1000	constructive-algorithms, greedy, implementation	1m 13s	✓
B	Bit Flipping	1300	bitmasks, constructive-algorithms, greedy	4m 54s	✗
C	Line Empire	1500	binary-search, brute-force, dp	1m 45s	✗
D	Reverse Sort Sum	1900	constructive-algorithms, data-structures, greedy	12m 5s	✗
E	AND-MEX Walk	2200	bitmasks, brute-force, constructive-algorithms	1m 55s	✗
F	Tree and Permutation Game	3000	dfs-and-similar, games, graphs	2m 6s	✓

Practice › Codeforces Solutions › Codeforces Round 782 (Div. 2) ›

CF 1659D - Reverse Sort Sum

We start with an unknown binary array $A$. For every prefix length $k$, we sort the first $k$ elements of $A$, leaving the rest unchanged. This produces $n$ arrays $B1, B2, dots, Bn$. Instead of seeing those arrays directly, we are given their column-wise sum $C$.

Practice › Codeforces Solutions › Codeforces Round 782 (Div. 2) ›

CF 1659F - Tree and Permutation Game

We are given a tree where every vertex hosts a position in a permutation. Separately, there is a token sitting on one vertex. The game evolves in alternating moves between Alice and Bob. Alice’s move does not change the tree.

Practice › Codeforces Solutions › Codeforces Round 782 (Div. 2) ›

CF 1659B - Bit Flipping

We start with a binary string. We must perform exactly (k) operations. In one operation we choose a position (i). The chosen bit stays unchanged, while every other bit in the string is flipped.

Practice › Codeforces Solutions › Codeforces Round 782 (Div. 2) ›

CF 1659E - AND-MEX Walk

We are given an undirected, connected graph where each edge has a non-negative integer weight less than $2^{30}$. A query asks for the minimum possible "length" of a walk from vertex $u$ to vertex $v$.

Practice › Codeforces Solutions › Codeforces Round 782 (Div. 2) ›

CF 1659C - Line Empire

We have a king starting at position zero on a number line, and there are several unconquered kingdoms at strictly increasing positions. The king wants to conquer all kingdoms at minimal cost.

Practice › Codeforces Solutions › Codeforces Round 782 (Div. 2) ›

CF 1659A - Red Versus Blue

We are asked to construct a sequence of match outcomes between two teams, Red and Blue, given the total number of matches, the number of wins for Red, and the number of wins for Blue.